MIS Chap # 7.....

MANAGEMENT INFORMATION
SYSTEM
Chapter 7
Systems Development
1

OVERVIEW
 System approach
 The Software Development Life Cycle
 Traditional SDLC
 Prototyping
 Rapid Application Development (RAD)
 Phased Development
 Business Process Redesign (BPR)
 Strategic Initiation of BPR Projects
 Reverse Engineering
 Reengineering
 System Development Tools
 Process Modeling, DFD, Use Cases 2

THE SYSTEMS APPROACH
 John Dewey identified three series of
judgments involved in resolving a
controversy:
• Recognize the controversy.
• Weigh alternative claims.
• Form a judgment.
 Systems approach
 a series of problem-solving steps that ensure
the problem is first understood, alternative
solutions are considered, and the selected
solution works.
3

SERIES OF STEPS
 Preparation effort
 prepares the problem solver by providing a
systems orientation.
 Business areas, level of management, resource flows
 Definition effort
 consists of identifying the problem to be solved and
then understanding it.
 Solution effort
 involves identifying alternative solutions, evaluating
them, selecting the one that appears best,
implementing that solution, and following up to
ensure that the problem is solved.
4

PHASES AND STEPS OF SYSTEMS APPROACH
5

EACH BUSINESS AREA IS A SYSTEM
6

DEFINITION EFFORT TERMINOLOGY
 Problem trigger
 is a signal that things are going better or worse than
planned.
 Symptom
 is a condition that is produced by the problem and is
usually more obvious than the root cause of the
problem.
 Problem
 is a condition or event that is harmful or potentially or
beneficial or potentially beneficial to the firm.
7

EACH PART OF THE SYSTEM IS
ANALYZED IN SEQUENCE
8

SELECT THE BEST SOLUTION
Analysis
 a systematic evaluation of options.
Judgment
 the mental process of a single manager.
Bargaining
 negotiations between several managers.
9

SYSTEMS DEVELOPMENT LIFE CYCLE
 SDLC
 is an application of the systems approach to
the development of an information system.
 Traditional SDLC stages are:
 Planning
 Analysis
 Design
 Implementation
 Use
10

THE CIRCULAR PATTERN OF THE
SYSTEM LIFE CYCLE
11

PROTOTYPING
 Prototype
 is a version of a potential system that provides
the developers and future users with an idea of
how the system in its completed form will
function.
 Prototyping is the process of producing a
prototype.
 Best suited for small systems–reflecting the
prototyping influence.
12

EVOLUTIONARY PROTOTYPE
 Evolutionary prototype
 is continually refined until it contains all of the
functionality that users require of the new
system.
 The steps involved are:
 Identify user needs.
 Develop prototype.
 Integrated application developer
 Prototyping toolkit
 Determine if the prototype is acceptable.
 Use the prototype. 13

DEVELOPMENT OF AN EVOLUTIONARY
PROTOTYPE
14

REQUIREMENTS PROTOTYPE
 Requirements prototype
 is developed as a way to define the functional
requirements of the new system when users
are unable to articulate exactly what they want.
 Begin with the Evolutionary Prototype steps, then the
next steps are:
 Code the new system;
 Test the new system;
 Determine if the new system is acceptable;
 Put the new system into production.
15

DEVELOPMENT OF A REQUIREMENTS PROTOTYPE
16

ATTRACTION OF PROTOTYPING
 Communications between the developer
and user are improved.
 The developer can do a better job of
determining the users’ needs.
 The user plays a more active role in system
development.
 The developers and the user spend less
time and effort developing the system.
 Implementation is much easier because the
user knows what to expect.
17

POTENTIAL PITFALLS OF PROTOTYPING
 The haste to deliver the prototype may
produce shortcuts in problem definition,
alternative evaluation, and documentation.
The shortcut produces a “quick & dirty”
effort.
 The user may get overly excited about the
prototype, leading to unrealistic
expectations regarding the production
system.
 Evolutionary prototypes may not be very
efficient.
 The computer-human interface provided by
certain prototyping tools may not reflect
good design techniques. 18

RAPID APPLICATION DEVELOPMENT
 RAD
 is a term coined by James Martin. It refers to a
development life cycle intended to produce
systems quickly without sacrificing quality.
 Information engineering (IE)
 is the name that Martin gives to his overall
approach to system development, which treats
it as a firm-wide activity.
 Enterprise
 is used to describe the entire firm.
 Essential to RAD is management, people,
methodologies, and tools.
 Best suited for large systems.
19

PHASED DEVELOPMENT
 Phased development
 is an approach for developing information
systems that consists of six stages:
 Preliminary investigation
 Analysis
 Design
 Preliminary construction
 Final construction
 System test
 Installation.
 Best suited for systems of all sizes. 20

THE STAGES OF THE PHASED
DEVELOPMENT METHODOLOGY
21

MODULE PHASES
 System is subdivided into major modules
such as:
 Report writer;
 Database;
 Web interface.
 Number of modules varies with the system
from one to a dozen or so.
 Stages are performed separately for each
module.
22

ANALYSIS, DESIGN, AND PRELIMINARY CONSTRUCTION ARE
PERFORMED ON EACH SYSTEM MODULE
23

BUSINESS PROCESS REDESIGN
 Reengineering or Business process redesign
(BPR) is the process of reworking the systems.
 Systems include both those that process the firm’s
data and those that perform basic functions such as
drilling for oil.
 BPR affects the firm’s IT operations in two
ways:
 Aids in the redesign of old information systems
(legacy systems);
 Applies to the redesign of information systems to
support major operations.
 Usually initiated at strategic management level
24

TOP-DOWN INITIATION OF BPR PROJECTS
25

STRATEGIC INITIATION OF BPR
 Reverse engineering
 is the process of analyzing an existing system
to:
 Identify its elements and their interrelationships;
 Create documentation at a higher level of
abstraction than currently exists.
 Functionality is the job that it performs.
 Reengineering
 is the complete redesign of a system with the
objective of changing its functionality.
 Forward engineering
 is given to the process of following the SDLC
in the normal manner while engaging in BPR.
26

BPR COMPONENTS
 BPR components can be applied separately or in
combination.
 Functional quality
 is a measure of what the system does.
 Technical quality
 is a measure of how well it does it.
27

BPR COMPONENT SELECTION IS BASED ON BOTH
FUNCTIONAL AND TECHNICAL QUALITY
28

METHODOLOGIES IN PERSPECTIVE
 Traditional SDLC
 is an application of the systems approach to the
problem of system development; contains all
elements.
 Prototyping
 is an abbreviated form focusing on the definition
and satisfaction of user needs.
 RAD
 is an alternative approach to the design and
implementation phases of SDLC.
 Phased development
 uses traditional SDLC and applies it in a modular
fashion.
29

SYSTEM DEVELOPMENT TOOLS
 Process modeling was first done with
flowcharts.
 ISO standards
 Use of 20+ symbols
 Data flow diagrams (DFD)
 is a graphic representation of a system that
uses four symbol shapes to illustrate how data
flows through interconnected processes.
 DFDs are excellent for modeling processes
at a summary level. 30

DATA FLOW DIAGRAM SYMBOLS
 Terminator
 describes an environmental element, such as a person,
organization, or another system.
 Environmental elements exist outside the boundary of the
system.
 Process
 is something than transforms input into output.
 Data flow
 consists of a group of logically related data elements that
travel from one point or process to another; can diverge and
converge.
 Data storage
 is a repository of data.
 Connector
 contains the number of the process that provides the data
flow. 31

A DFD OF A SALES COMMISSION SYSTEM
32

LEVELED DATA FLOW DIAGRAMS
 Leveled DFDs is used to describe the hierarchy of
diagrams, ranging from context to lowest-level n
diagram.
 Diagram identifies the major processes of a system.
 Use additional DFDs to achieve documentation at both a
more summarized and a more detailed level.
 Context diagram is a diagram that documents the
system at a more summarized level.
 Positions the system in an environmental context.
 Figure n diagram is a diagram that provides more
detail.
 n represents the # of processes on the next higher level.
 Documents a single process of a DFD in greater detail
33

A CONTEXT DIAGRAM OF A SALES
COMMISSION SYSTEM
34

A FIGURE 4 DIAGRAM OF A SALES
COMMISSION SYSTEM
35

USE CASES
 Use case
 is a narrative description in an outline form of
the dialog that occurs between a primary and
secondary system.
 Continuous narrative format
 with each action numbered sequentially.
 Ping-pong format
 consists of two narratives and the numbering
indicates how the tasks alternate between the
primary and secondary systems.
 Alternative events are actions that are not
normally expected to occur; alphabetic
letters are appended to step numbers. 36

PROJECT MANAGEMENT
Steering committee
 is a committee with the purpose of
providing ongoing guidance, direction,
and control of all systems projects.
MIS steering committee
 purpose is directing the use of the firm’s
computing resources.
 It establishes policies.
 It provides fiscal control.
 It resolves conflict. 39

MANAGERS OF A SYSTEM LIFE CYCLE
ARRANGED IN A HIERARCHY
40

PROJECT LEADERSHIP
 Project team
 includes all of the persons who participate in the
development of an information system.
 Team leader (project leader)
 provides direction throughout the life of the
project.
41

PROJECT MANAGEMENT MECHANISM
 Basis for project management is the project
plan.
 Gantt chart
 is a horizontal bar chart that includes a bar for
each task to be performed; bars arranged in time
sequence.
 Network diagram (CPM diagram, PERT
chart)
 is a drawing that identifies activities and links them
with arrows to show the sequence in which they
are to be performed.
 Narrative reports are in the form of weekly
written reports by project leader, communicates
project information to MIS steering committee.
42

PROJECT COST ESTIMATING
 Cost-estimating inputs
 Work breakdown structure (WBS)
 Resource requirements, resource rates
 Activity duration estimates
 Historical information
 Cost-estimating tools and techniques
 Bottom-up estimating
 Computerized tools
 Mathematical models
 Cost-estimating outputs
 Supporting details
 Cost-management plan
45

COMPONENTS OF COST-ESTIMATING
PROCESS
46

MIS Chap # 7.....

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MIS Chap # 7.....